Mechanical properties of phenolic composites reinforced with jute/cotton hybrid fabrics

Mechanical properties (tensile, flexural, impact, and dynamic mechanical thermal analysis) of novolac type phenolic composites reinforced with jute/cotton hybrid woven fabrics were investigated as a function of fiber orientation and roving/fabric characteristics. Scanning electron microscopy (SEM) was carried out to investigate the fibermatrix adhesion. Results showed that the composite properties are strongly influenced by test direction and rovings/ fabric characteristics. The anisotropy degree was shown to increase with test angle and to strongly depend on the type/architecture of fabric used, i.e., jute rovings diameter, relative fiber content, etc. It was possible to obtain composites with higher mechanical properties and lower anisotropy degree by producing cross-ply laminates. Best overall mechanical properties were obtained for the composites tested along the jute rovings direction. Composites tested at 45degrees and 90degrees with respect to the jute roving direction exhibited a controlled brittle failure combined with a successive fiber pullout, while those tested in the longitudinal direction (0degrees) exhibited a catastrophic failure mode. Our results indicate that jute promotes a higher reinforcing effect and cotton avoids catastrophic failure. Therefore, this combination of natural fibers is suitable to product composites for lightweight structural applications. POLYM. COMPOS., 26:1-11, 2005. (C) 2004 Society of Plastics Engineers